Web Services Conceptual Architecture
- H. Kreger
- Techn Report, IBM, WCSA 1.0,
Due to the characteristics of wireless mobile networks (e.g., node mobility, request fluctuation, poor quality of service), operators as well as service and content providers must cooperate to satisfy their customers. One of the solutions is the dynamic reconfiguration of service platforms, which is a real-time operation made on an initial configuration to improve the QoS parameters of the platform. Reconfiguration can be done by software means, and it can be material or logical, meaning that it may affect the physical or software components of the platform, the physical links, or also the transmitted information, without deteriorating the SLAs contracts signed between customers and operators. Several works have been already published in this direction but they fail in presenting a global view and a generic solution for the problem. This work is articulated in the form of a synthesis of the various solutions of reconfiguration which take place with coherence on the various levels of intervention. To this purpose, a model of a platform has been first developed; traffic and mobility models have been also injected to predict the movement and the demand pattern of the users. Moreover, several scenarios of reconfiguration were proposed for the change or the migration of software components, for the management network, the information routing, and the adaptation of the data. In a first part, we address the reconfiguration problem as a mono-objective optimization problem subjected to several constraints. We propose a mathematical model to deal with this situation. However, we found that finding rigorous solutions for this problem may have a huge computational cost. Hence, we also propose an alternative method introducing flow deviation and heuristics in the genetic algorithm. In the second part of our work, we deal with the behavioural aspect of the problem. It consists in considering the different metrics simultaneously and to seek a whole solution configuration representing various interesting compromises between the resources networks and the classes of services and users.